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Because of how long it takes to form underground and then it moves to the surface and cools rapidly
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Explanation:
1. Explain how groups 1A-8A in the periodic table are organized by their number of valence electrons.
The valence electrons in an atom are the outermost shell electrons. They are the most loosely held electrons in an atom.
Coincidentally, the periodic table of elements divided into vertical groups and horizontal periods can be said to be arranged according to the number of valence electrons.
- Atomic numbers are used to arrange elements on the periodic table.
- Down a group, the number of electronic shell increases. More electrons are added to new energy levels.
- As we move from left to right across a period, the number of electrons in elements increases but electronic shell is the same.
- Down a group electronic shell increases but the number of valence electrons are the same.
- All elements in Group 1A has just one valence electrons, Group 2A has two valence electrons.........Group 8A has eight valence electrons.
- Moving across groups is synonymous to moving from left to right on the periodic table.
- Due to this trend, the periodic table is arranged based on the number of valence electrons.
3. explain how you know the number of valence electrons for each group.
The number of valence electrons in a group is the group number:
Group Number valence electrons
1A 1
2A 2
3A 3
4A 4
5A 5
6A 6
7A 7
8A 8
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Periodic table brainly.com/question/1971327
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The mass of 2.80 grams of h2o is 18.02 amu I believe
1) Write the balanced equation to state the molar ratios:
<span>3H2(g) + N2(g) → 2NH3(g)
=> molar ratios = 3 mol H2 : 1 mol N2 : 2 mol NH3
What volume of nitrogen is needed to produce 250.0 L of ammonia gas at STP?
First, convert the 250.0 L of NH3 to number of moles at STP .
Use the fact that 1 mole of gas at STP occupies 22.4 L
=> 250.0 L * 1mol/22.4 L = 11.16 L
Second, use the molar ratio to find the number of moles of N2 that produces 11.16 L of NH3
=> 11.16 L NH3 * [1 mol N2 / 2 mol NH3] = 5.58 mol N2
Third, convert 5.58 mol N2 into liters at STP
=> 5.58 mol N2 * [22.4 L/mol] = 124.99 liters
Answer: 124,99 liters
What volume of hydrogen is needed to produce 2.50 mol NH3 at STP?
First, find the number of moles of H2 that produce 2.50 mol by using the molar ratios:
2.50 mol NH3 * [3mol H2 / 2 mol NH3] = 3.75 mol H2
Second, convert the number of moles to liters of gas at STP:
3.75 mol * 22.4 L/mol = 84 liters of H2
Answer: 84 liters
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This question is describing the following chemical reaction at equilibrium:
And provides the relative amounts of both A and B at 25 °C and 75 °C, this means the equilibrium expressions and equilibrium constants can be written as:
Thus, by recalling the Van't Hoff's equation, we can write:
Hence, we solve for the enthalpy change as follows:
Finally, we plug in the numbers to obtain:
![\Delta H=\frac{-8.314\frac{J}{mol*K} *ln(0.25/9)}{[\frac{1}{(75+273.15)K} -\frac{1}{(25+273.15)K} ] } \\\\\\\Delta H=4,785.1\frac{J}{mol}](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5Cfrac%7B-8.314%5Cfrac%7BJ%7D%7Bmol%2AK%7D%20%2Aln%280.25%2F9%29%7D%7B%5B%5Cfrac%7B1%7D%7B%2875%2B273.15%29K%7D%20-%5Cfrac%7B1%7D%7B%2825%2B273.15%29K%7D%20%5D%20%7D%20%5C%5C%5C%5C%5C%5C%5CDelta%20H%3D4%2C785.1%5Cfrac%7BJ%7D%7Bmol%7D)
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